The value of 18F-FDG PET/CT in patient with neurofibromatosis type 1

Abstract

Rationale:Neurofibromatosis type one (NF1) is characterized by cutaneous and nervous lesions, and the tendency to form plexiform neurofibromas (PNFs). PNFs may undergo malignant transformation into a malignant peripheral nerve sheath tumors (MPNSTs). MPNSTs often carry an significant morbidity and mortality.Patient concerns:A 17-year-old man with gradually increased multiple subcutaneous soft lesions. He also presented with numerous lentigines and multiple café-au-lait macules on his body.Diagnoses:These were collagen neurofibroma, which were definitively diagnosed by pathology. NF1 was eventually diagnosed.Interventions:These lesions were abnormal uptake of radiotracer, when he underwent positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) scanning. Standard uptake value (SUV) and other parameters can help to distinguish benign and malignant lesions in patient with NF1. He was underwent serials 18F-FDG PET/CT examinations to followed up, in order to monitor these lesions malignant transformation.Outcomes:So far, these subcutaneous soft lesions were not malignant transformation.Lessons:18F-FDG PET/CT is being increasingly used as an imaging modality to discover the systemic lesions and to discriminate between benign and malignant plexiform neurofibromas.

Nerve Tumors of the Upper Extremity

“…Serial 18 F FDG-PET/CT scans have been used for monitoring lesions in patients with NF1 for malignant transformation. 14 When clinical and radiological findings are not clearly consistent with a benign nerve sheath tumor, a core needle biopsy should be performed, although it can be painful. 11 For a lesion without suspicious malignant characteristics and clinical and radiological findings of a benign nerve sheath tumor, a marginal excision can be performed.…”

PET Imaging of Peripheral Nerve Tumors

“…17 To address this issue, several studies have assessed the ability of fludeoxyglucose (FDG)-PET with or without CT to distinguish benign from malignant primary PNT based on a tumor's metabolic activity. 17,[19][20][21][22] In general, benign PNTs depict no or low FDG uptake, whereas malignant PNTs demonstrate moderate to high FDG accumulation. In these studies, standard uptake values (SUV), a quantitative amount of FDG uptake, range between 1.0 and 3.99 in benign PNTs and between 3.1 and 21.4 in malignant PNTs.…”

Neurofibromatosis 1 associated to malignant peripheral nerve sheath tumor: A radiological approach

“…Por último, y si bien su uso en nuestro medio aún no está muy extendido, es importante conocer lo que permite valorar la PET-TC, la cual cobra su importancia en la diferenciación de lesiones benignas y malignas a través de la medición del valor de absorción estándar para fluor-18-fluorodesoxiglucosa (18F-FDG); existen además otros parámetros medibles como el volumen tumoral metabólico y glicólisis total de la lesión, pero no existe evidencia suficiente aún que justifiquen su uso rutinario (12).…”